Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
danh kien » dinh kien, danh viet, linh kien
dan danh » van danh, han danh, ban danh
kien cua » khien cua, dien cua, tien cua
doc hai » hoc hai, duc hai, do hai
ky tang » ky nang, ky dang, kho tang
tang xa » trang xa, tang ma, lang xa
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
hai ky » thai ky, hoi ky, hai ly

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: doc hai ky tang xa hoi. hieu va ((tham thuc) or (am thuc)) dan danh kien cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hai ky tang xa hoi. hieu va ((tham thuc) OR (am thuc)) dan danh kien cua tre.
• Adding a wildcard symbol may retrieve word variants: doc hai ky tang xa hoi. hieu va ((tham thuc) or (am thuc)) dan danh kien cua tre*.